[Diy_efi] OT - Measuring less than an ounce

[Ernest Buckler]

Dan,
For starters, I'd suggest doing a similar exercise with 16 oz cans of soup 
or veggies at 1:1, then 2:1 length, then gradually stepping back, making the 
occasional suggestion ("maybe we could use pennies...?" & "what happens if 
we...?").   Also, you don't really need wt in ounces, as long as pennies and 
uniquely-named (funny?) fractions thereof remain her standard  throughout 
her experiment.  She will probably conclude that herself somewhere along the 
way, as long as you don't give her too many of our mainstream limits. Or 
maybe softly offer a tiny example, etc.  She's basically duplicating early 
measuring methods of early civilization, with some natural (and visible) 
math thrown in (the ratio stuff). I would also bet that somewhere along the 
line she will see ways to improve the instrument itself, to make it easier 
to use and more consistent...   If you just hang out with her and go 
"hmmm.." a lot, and occasionally ask "how can we do this next thing , based 
on what we already know?", let it sink in over several days, I'll  bet she 
will get it figured out herself.   And that WILL stick with her.  I'm 
presuming that as YOUR child, she's already pretty doggone smart; she might 
just surprise you with how much of this she can and will do on her own, 
given space AND impetus ("well, this HAS to get figuered out, you know. 
Hmmm.  What do you think here?")  Your challenge will be to back off and 
steer with tiny nudges, of course. Plus checking the logic and ensuring 
accuracy, most gently.   As it was mine, but having a psychologist wife who 
had also studied Montessori, helped.

Sorry, but you did ask.

Ernest B.



----- Original Message ----- 
From: "Daniel Nicoson" <A6intruder at myo-p.com>
To: "DIY_ EFI" <diy_efi at diy-efi.org>
Sent: Thursday, January 11, 2007 7:24 PM
Subject: [Diy_efi] OT - Measuring less than an ounce


>I hope you guys don't mind this totally Off Topic, but you are one of my
> more scientific group of friends.
>
> I need somebody to review my physics/methodology below:
>
> Helping my daughter (16 yr old) with a science project.  She is testing 
> two
> types of fertilizer by growing three equal size patches of grass, 
> fertilizer
> A, fertilizer B, Control.
>
> Here's the real problem:  We need to measure VERY small amounts of 
> granular
> fertilizer.  The grass patches are only .38 ft^2, one fertilizer amount
> comes out to .0213 ounces, the second comes out to .24 ounces.
>
> I don't know about you but I don't have that kind of scale around here.
>
> Here's my idea, please scrutinize, simplify, accurize...
>
> I am going to weigh 300 pennies tomorrow at work on an electronic postal
> scale, I think it reads out in 10ths of ounces.  If they read greater than 
> 1
> ounce I should get 2 significant digits, possibly they will weigh more 
> than
> 10 ounces and we can work with 3 significant digits.  The assumption is 
> that
> the pennies all weigh the same.  This will give me an accurate weight of 
> one
> penny.
>
> Back home this weekend we will make a simple balance beam.  Since I don't
> have jeweled bearings, I'm thinking a simple string at the fulcrum will 
> give
> as consistent results as anything.
>
> At the short end, say 10-to-1 ratio of lengths, I will have a hanging
> container with pennies.  At the other end I will have a plastic medicine
> bottle to hold the fertilizer.
>
> To zero the balance scale out I will add coins (any size) until the coins
> balance out the whole apparatus.
>
> Next, I will have to do the math as to how many pennies equal 10 times the
> weight of the desired fertilizer weight.  Place this measured amount of
> weight in pennies on the short end of the balance.  Next, fill the 
> medicine
> bottle with fertilizer until it balances.
>
> Done, measured, accurate weight of fertilizer.
>
> Does all of that make sense?  It does to me.
>
> The hardest part will be helping her learn what we just did so she can
> defend her process on the project.
>
> Suggestions are appreciated.
>
> Dan Nicoson
>
>
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